MySQL 和 MariaDB 一些限制和BUG

字段属性限制

1、不支持 CHARACTER SET 语法

MariaDB [test]> create table t1(id int,name varchar(10) CHARACTER SET utf8) engine=Columnstore;
ERROR 1178 (42000): The storage engine for the table doesn’t support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

2、不支持COLLATE语法

MariaDB [test]> create table t1(id int) engine=Columnstore COLLATE=utf8_bin;
ERROR 1178 (42000): The storage engine for the table doesn’t support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.


MariaDB [test]> create table t1(id int,name varchar(10) COLLATE utf8_bin) engine=Columnstore;
ERROR 1178 (42000): The storage engine for the table doesn’t support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

3、不支持TEXT/BLOB

MariaDB [test]> create table t1(id int,info text) engine=Columnstore;
ERROR 1178 (42000): The storage engine for the table doesn’t support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.


MariaDB [test]> create table t1(id int,info blob) engine=Columnstore;
ERROR 1178 (42000): The storage engine for the table doesn’t support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

4、Datatime 不支持 CURRENT_TIMESTAMP, 后面的 DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP 全部删除，timestamp 支持 CURRENT_TIMESTAMP

MariaDB [test]> create table t1(update_time timestamp)engine=Columnstore;
ERROR 1178 (42000): The storage engine for the table doesn’t support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

MariaDB [test]> create table t1(update_time timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP) engine=Columnstore;
ERROR 1178 (42000): The storage engine for the table doesn’t support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

5、decimal 不能大于18

MariaDB [test]> create table t1(money decimal(19,2)) engine=Columnstore; 
ERROR 1815 (HY000): Internal error: CAL0009: (3)Create table failed due to Syntax error: The maximum precision (total number of digits) that can be specified is 18

6、不支持 ROW_FORMAT=COMPACT

MariaDB [test]> create table t1(id int)engine=Columnstore ROW_FORMAT=COMPACT;
ERROR 1178 (42000): The storage engine for the table doesn’t support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

7、varchar最大8000

MariaDB [test]> create table t1(name varchar(8001))engine=Columnstore;
ERROR 1815 (HY000): Internal error: CAL0009: (3)Create table failed due to char, varchar and varbinary length may not exceed 8000

8、不支持bit类型

MariaDB [test]> create table t1(status bit)engine=Columnstore;
ERROR 1178 (42000): The storage engine for the table doesn't support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

9、comment不能携带’’引号

MariaDB [test]> create table t3(id int comment '主键''ID')engine=Columnstore;
ERROR 1178 (42000): The storage engine for the table doesn't support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

10、行溢出，一行varchar不能大于65535（UTF8要除以3）

ERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. This includes storage overhead, check the manual. You have to change some columns to TEXT or BLOBs

11、不支持enum枚举类型

MariaDB [test]> create table t1(`type` enum('HOLIDAY','WORKDAY') DEFAULT NULL)engine=Columnstore;
ERROR 1178 (42000): The storage engine for the table doesn't support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

12、不支持zerofill

MariaDB [test]> create table t2(id int(6) zerofill)engine=columnstore;       

ERROR 1178 (42000): The storage engine for the table doesn't support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

BUG

不支持 Reserved keywords 保留关键字user、comment、match、key、update、status

https://jira.mariadb.org/browse/MCOL-1022

MariaDB [test]> create table user(id int)engine=Columnstore;
ERROR 1178 (42000): The storage engine for the table doesn’t support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

MariaDB [test]> create table t1(comment varchar(100))engine=Columnstore;
ERROR 1178 (42000): The storage engine for the table doesn’t support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

SQL语句限制

1、distinct的字段不在order by里，就不能排序 https://jira.mariadb.org/browse/MCOL-1036

MariaDB [test]> select distinct apply_time from test ORDER BY id limit 1;          

ERROR 1178 (42000): The storage engine for the table doesn't support IDB-2022: ORDER BY column not in DISTINCT list.

2、查询的字段不在group by里，就不能分组统计

MariaDB [test]> select id from test group by qq;  
ERROR 1815 (HY000): Internal error: IDB-2021: 'test.id' is not in GROUP BY clause. All non-aggregate columns in the SELECT and ORDER BY clause must be included in the GROUP BY clause.

3、alter不支持change/modify更改字段属性

MariaDB [test]> alter table t1 change id id bigint;
ERROR 1815 (HY000): Internal error: CAL0001: Alter table Failed:  Changing the datatype of a column is not supported

4、alter不支持多列操作和不支持after

MariaDB [test]> alter table t1 add age tinyint,add address varchar(100);
ERROR 1178 (42000): The storage engine for the table doesn't support Multiple actions in alter table statement is currently not supported by Columnstore.

MariaDB [test]> alter table t1 add age tinyint after id;  
ERROR 1178 (42000): The storage engine for the table doesn't support The syntax or the data type(s) is not supported by Columnstore. Please check the Columnstore syntax guide for supported syntax or data types.

5、字段类型不同 join 关联查询报错

MariaDB [test]> select t1.id from t1 join t2 on t1.id=t2.cid;
ERROR 1815 (HY000): Internal error: IDB-1002: 't1' and 't2' have incompatible column type specified for join condition.

6、DML语句会非常慢

DML, i.e. INSERT, UPDATE, and DELETE, provide row level changes. ColumnStore is optimized towards bulk modifications and so these operations are slower than they would be in say InnoDB.
Currently ColumnStore does not support operating as a replication slave target.
https://mariadb.com/kb/en/library/columnstore-data-ingestion/

7、大批量数据导入text字段报内存不足

Internal error: CAL0001: Insert Failed: IDB-2008: The version buffer overflowed.
https://jira.mariadb.org/browse/MCOL-1056

8、不支持replace into和load data infile replace into

https://jira.mariadb.org/browse/MCOL-1080

MariaDB官方回复：覆盖写目前优先级较低，因为这是一个非常大的项目，预计执行成本很高。